"Blame the extraterrestrials for this style of interviewing. In 1950 the subject of flying saucers came up one day around lunchtime at
"'Edward, what do you think?' the physicist Enrico Fermi asked his tablemate Edward Teller. Was it possible that extraterrestrials were visiting the earth in spaceships? Teller judged it highly unlikely. Fermi was no so sure. He spent much of his lunch calculating how many extraterrestrial civilisations there were in the universe and how close the nearest one would be.'
"This was the classic 'Fermi question.' Back at the
"Today's employers have gotten the idea that everyone, including humanities graduates, should be able to estimate odd quantities on a job interview. (No one is expected to estimate weird things after they're hired.) These questions are today's riddle of the sphinx. They often determine who gets to pass from phone interview to the corporate campus. Some are loosely related to the company's line of business:'
"How many petrol stations are there in the
"But more often, there's no discernible connection:'
"How many rubbish collectors are there in
"Estimate the number of taxis in
"How many golf balls would fit in a stadium? (JP Morgan Chase)'
"Estimate the costs of producing a bottle of Gatorade (a
"How many vacuum cleaners are made a year? (Google)'
"An advantage of Fermi questions – for employers – is that it's easy to invent new ones. Thus the candidate can be presented with a fresh question that's never been in a book or on the web."
(pp. 108-9, 'Are You Smart Enough to Work at Google? Fiendish puzzles and impossible interview questions from the world's top companies' By William Poundstone - Landmark)